Comment 18 for bug 1432194

Logging out and logging in will sometimes fix the issue for me, but only temporarily. More info, changing fonts in a particular application will generally cause the letters to be rendered correctly. Changing back (in the same session) will show the missing letters again. This happens on all of Ubuntu 14.04, Ubuntu 14.10, Kubuntu 14.10 on a Thinkpad T450s. (It is least problematic on Kubuntu 14.10). Hope this extra bit of info helps.